In educating myself about Mylar (PET) films I did run across several WHITE OPAQUE Mylar films. I haven't as yet found all the necessary info to determine if they could be considered for our use... but I'll list the designations...

Im leaning toward 4 mil for a bit more durability but could drop down to a 3 mil as that is the thickness Ultra Efficient Products used on the original Invaders and provided in their covering kits. Both demonstrator aircraft... the taildragger and tri-gear used Mylar to cover the center section, both outer main wing panels, and the ruddervators. The plans built aircraft I have seen over the years (in person and photographs) were fairly evenly divided between Mylar and fabric. The wing construction of this design just demands a clear or translucent covering in my opinion.

I own plan set #340 but I have absolutely no idea on the total number of plan sets sold or number of aircraft completed. Im considered the defacto expert on this design but truthfully... my historical knowledge is woefully lacking.

I been able to winkle out a bit more information regarding the Tedlar films. Type 3 films can either be transparent or pigmented. If one wasnt stuck on having a transparent film heres some color designations Ive compiled...

So if for example... you wanted your covering to be GLOSSY SUN YELLOW... you would want a TLY20BG3 film. If you wanted LOW gloss, MEDIUM gloss, or SATIN gloss... substitute L, M, or S for the G in the designation. For a GLOSSY PEPPER DUST colored film... TPD20BG3... do the substitution for the suface appearance you desire.

The pigmented films are UV barrier films and actually perform better than the UV screening transparent films. The UV screening films are surface coated and the coating loses approx 45-50% of its screening abilities after 5 years.

Im thinking the darker colors might not be appropriate due to heat absorbtion and the possiblity to slacken the film... but thats just an assumption.

Even though the selection of films has widened... same problem as before... finding a supplier.

Wow, that some interesting information. You are definitely doing some in-depth research for your project. If you put this much time into the remainder of your Invader project you should end up with a show plane.

While on the subject have you run across any sources for clear Mylar or Tedlar tapes of the proper thickness (2mil) in the 2.5" to 3.0 " wide range. Finding the proper film may only be half the battle as the needed tapes seem to be just as elusive.

You simply shrink everything down first and THEN apply the 2" wide tape.

The stuff Naggy was selling is thick and plyable but the problem is that if you stretch it slightly it tends to pop up and come unglued.

Im hoping some time in the sun will harden the tape glue a bit more so that it stays put.

I also bought some greenhouse repair tape and it is perfect, and does not have the same problem as the other stuff.

Naggy had maybe 300' of Tedlar left in September, so odds are that he is sold out by now, and dont even bother with the Tapes.

I used the 3M VHB Foam Tape and the Double sided 1/2" and 3/4" #9649 I think and this stuff is awesome. Fantastic holding power.

I also used the 3M Metalic mylar tape as opposed to the Metal tape, its much easier to work with and only 1mil thick also awesome stuff, but only to cover other tapes as it does not have the adhesive strength to hold the skins down.

If anyone wants a sample to see what I used, just ask, I have tons left over.

Anyone try that red Tyvek tape on Tedlar? That stuff is super sticky and strong as well and would probably work to...I understand you can get it in clear and white as well.

I was a little apprehensive to try these alternate tapes at first but when I compared them to the originals, you can see that improvements have been made in tape products over the years.....so I would not be afraid to try one of the newer ones.

After flying 2005 on these tapes I'll post the results on how they held up, so you can also try the new tapes with confidence.

No point in us reinventing the wheel.....lets posts our tape experiences good or bad so that we can used the best available.

I suspect the people going to Hipec etc are just scared about using tapes, so maybe we can validate our findings so more people don't have to go that route, unecessarily.

Ray

<H5>Nothing is impossible...Even the word tells you Im-Possible!!!</ H5>

I've spent so much time on the films I haven't had much of a chance to research tapes. I just did a quick look-see and find the WHITE Tedlar tapes to be readily available but CLEAR is a bit more difficult to locate. It seems the Hi-performance KITE industry uses clear Tedlar tapes for repair but offer only short lengths retail. Same with the greenhouse industry. I can find a 2" clear Tedlar tape but only in a 7' roll. I did find Tedlar tape used in the electronics industry as a protective overlay. It's offered in CLEAR in widths and lengths we can use.

The greenhouse POLY tapes could certainly be candidates as they posess all the characteristics we want. A bit of testing and testimonials would certainly help here.

I'm considering the 3M 9460 ADHESIVE TRANSFER TAPE as my seam bonding tape. I do not have the surface discontinuities found in the Lazair wing and feel I do not need the foam type tapes. Also the higher heat needed to shrink some of the alternative films exceed some of the tape temperature limits. The 9460 is a HIGH temp tape and will tolerate the elevated shrink temperatures. I'm getting a roll to test.

The attachment shows a few of the tapes I've located...

Steve
Crooked River Ranch, OR

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senna12625 @ Dec 10 2004, 10:10 PM wrote: Well... I finally found a supplier for one of the many films I have been looking for. It's MELINEX 516 PET film (Mylar)... a direct replacement film for MYLAR D film which DuPont has discontinued. This particular Melinex film is non-treated and has a very high clairty. I found it in a 60 inch width and in 100 and 250 ft rolls depending on which thickness you desire. As an example...

Ola the guy who made did all this research on the different coverings is Steve Butcher. If you read the earlier posts made by him you know he was looking for original type Mylar for his Invader Mark IIIB project. If you want to get with him for more information you should go over to the Invader Yahoo group, Here at :
http://groups.yahoo.com/group/Invader_MarkIII/